Fears that a gunman, then a loose gun, were on a BART train delayed the Richmond line for as long as 30 minutes Thurs-day, a BART spokesman said.

About 11:54 a.m., a transit rider called BART police to report seeing a man get on a train with a gun sticking out of his pants. System engineers held the southbound train at North Berkeley until BART police arrived, searched the train and did not find anyone with a gun, said BART spokesman Linton Johnson.

However, witnesses helped BART and Berkeley police track down a man outside the station fitting the description given by the original caller. The man had no weapon, but was a parolee with an outstanding arrest warrant, so police arrested him, Johnson said.

“BART police were worried that the suspect may have ditched the gun on the train, potentially creating a situation where someone might find the gun and use it either accidentally or on purpose,” Johnson said.

The train had left the station, so police halted it three stops down the line, at MacArthur Station. Police searched it again and found no weapon.

The train was released for the second time at 12:18 p.m., delaying five trains for as long as 30 minutes.